OAEBOi!*lFEROUS SPECIES. 53 



both horizontal and vertical, show its internal structure very clearly. In 

 its short, rai^idly-expanding form, as well as in the divaricating arrangement 

 of its septa along the middle of its dorsal side, and in the position of its fos- 

 sula, it nearly resembles the form I have referred to Z. muUilameUa. From 

 that species, however, it is readily distinguished by having its septa much 

 more closely crowded, and particularly by having a very wide space within 

 occupied by nearly straight, crowded tabulas. 



I know of no described species, either American or foreign, with which 

 it is liable to be confounded. 



Locality and position. — Boxelder Peak, Wasatch Range, Utah ; Carbon- 

 iferous limestone. 



ZaPHKENTIS 1 MULTILAMELLA, Hall ?. 

 Plate fi, Cga. 4, 4 a, 4 b. 

 Zophrcntis? muUilamella, Hall (1852), Stansbury's Report Explorations of Gieat Salt 

 Lake Valley, 408, pi. i, fi^. 2. 



Corallum subturbinate, slightly curved, rapidly expanding; calice cir- 

 cular, of moderate depth; septa thin, about 1.50 to 160 in specimens meas- 

 uring one and tlii-ee-fourths to two inches in diameter, alternately longer 

 and shorter, the latter extending one-third to one-half way inward, and the 

 longer apparently reaching the middle of the calice; fossula narrow, deep, 

 and extending inward from the convex side of the corallum nearly to the 

 middle; outer vesicular zone apparently less than half the semi-diameter; 

 vesicles somewhat elongated, and arranged obliquely outwaid and upward; 

 those of the inner :area formed by the complex nature of the tabular, 

 arranged more or less obHquely upward and inward. Epitheca thin, and 

 usually destroyed on weathered specimens, showing obscure septal costae, 

 with small wrinkles and low undulations of growth; costee, and, in 

 weathered specimens, the edges of the septa, divaricating upward at acute 

 angles along an imaginary line up the middle of the convex side coincident 

 with the fossula. 



Length, measuring along the outer side of the curve, about 3 inches; 

 breadth, 2 inches. 



Professor Hall's figure of his Z. multilameUa shows little more than its 

 general form, and that it has a moderately deep calice; while his description 



